What are some docker alternatives? And how does Docker on windows work? I know it uses Hyper-V underneath but does MS include a base linux kernel image?
Docker on Windows is interesting. For windows containers, it can do both process based isolation (similar to Docker on Linux) and Hyper-V based isolation, which uses a very cut down VM as a base. Compared to Linux containers the base images are large, but there are only a few commonly used base images, so once you've got them it's not too horrible due to the overlay filesystem in use.
For Linux containers there is LCoW, which uses a Linuxkit VM to host the containers.
There is also some chance that in the future Linux containers will run natively on Windows without a VM, via WSL. This is very hacky at the moment but there have been reports of people being able to run Docker engine in WSL with no VM.
I always thought WSL was only meant to be a dev-tool. Do you have any links where there is a mention of a plan for them to be prod? (I know that's not what you're mentioning but wondering if that's how you guessed...)
Whether MS ever use that tech. for production linux containers remains to be seen. It sounds kind of cool and might be good enough for dev/test but I imagine sorting out all the wrinkles to make it prod. ready could be tricky...
